U.S. Pat. No. 5,662,066 entitled AUTOMATIC CAT LITTER DEVICE AND METHOD is incorporated herein by reference.
1. Field of the Invention
This invention relates to the field of animal husbandry, and more specifically to a liter box device having means for automatically separating animal waste from absorbent litter material.
2. Description of the Related Art
This invention provides improvements to the automatic cat litter device that is described in U.S. Pat. No. 5,662,066 that describes a cat litter device having a hollow rotatable sphere-shaped chamber that sits on top of a support pad. The support pad is in the shape of a hollow and upright cylinder. It is suggested that the support pad be formed in a frusto-conical section for additional strength and stiffness. The chamber holds a supply of litter, it is rotatable about a generally horizontal axis, and it is supported on the upper part of the support pad by way of low-friction support means. A first opening in the chamber provides for the entrance and exit of a cat, and second openings are provided whereby waste material may be dropped into a waste storage bag that is contained within the support pad. Periodically, the chamber rotates and a screen that is within the chamber then operates to separate animal waste from the litter; i.e., the litter is cleaned of waste. Continued rotation of the chamber then causes the separated waste to drop out of the chamber and into the storage bag, whereupon the chamber returns to its original position. The chamber may rotate at periodic time intervals, or it may rotate at a time interval after the presence/absence of a cat within the sphere-shaped chamber has been detected. The use of a motion detector is suggested to detect use by the cat. The rotatable chamber carries magnets. A Hall-effect sensor detects the magnets, and thereby detects the rotational position of the chamber. A controller responds to the output of the Hall-effect sensor and controls a bi-directional motor that operates to rotate the chamber.
U.S. Pat. No. 4,120,264 is also of general interest in that it provides a sanitary facility for pets that includes a rotatable chamber that contains pet litter. A grate is provided within the chamber to allow clean litter to pass therethrough, but to retain and thus separate agglomerated litter and solid animal excrement. Gravity and the grate cooperate as the chamber is rotated to move matter retained on the grate so as to exit the chamber.
Relatively simple open top plastic boxes that contain a quantity of litter are known, and it is also known that when litter is to be periodically changed, the box is manually inverted to thus allow the spent litter and the waste that is contained therein to gravity fall into a garbage container or the like. In this manual box emptying process, it is sometime necessary to use the hand to pound on the bottom of the box, and/or it may be necessary to manually scrape the bottom of the box with a tool to ensure that all spent litter is released from the bottom of the box.
While the art provides a number of sanitary facilities or cat litter devices for use by pets such as cats, the need remains in the art for improvements to such facilities and devices.
This invention provides a new and an unusual sanitary device or litter device for use by pets and animals such as cats.
Devices in accordance with this invention include a rotatable chamber whose bottom surface includes a flexible liner (for example, a liner that is made of the synthetic thermo plastic elastomer (TPE) such as the brand Santoprene), and preferably a weighted flexible liner. A quantity of litter is placed on top of this flexible liner, the litter taking the physical shape of a relatively thick layer or pile. In an embodiment of the invention, the device held about 14-pounds of litter.
As a pet makes use of the sanitary device, urine and solid waste is deposited on top of and within the mass of litter. Later, and after the pet has exited the chamber, automatic inversion of the chamber causes the quantity of litter to gravity fall through a screen whose opening size (about xc2xc-inch square) allows only clean litter to pass therethrough. That is, urine/litter clumps and solid waste is retained on the screen for disposal to a waste bag.
The flexible liner also gravity falls when the chamber is placed in this inverted position. The resulting flexing and movement of this liner ensures that all of the litter, including all of the litter clumps, are released from the liner to then fall toward the above-mentioned screen.
As used herein, the term screen is intended to mean any member that separates course particles from finer particles, and more specifically, any member that separates solid animal waste, including clumps that are formed when urine wets litter from relatively clean litter particles.
As a feature of the invention, the bottom of the chamber includes one or more air holes that prevent vacuum adherence of the liner to the wall of the chamber, and as an additional feature of the invention, the air hole size is selected to control the rate of gravity falling or movement of the flexible liner when the chamber is placed in the inverted position.
When the chamber is in the shape of a sphere, the above-mentioned liner is in the shape of a hemisphere; for example, a polymer material that is pre-formed in the shape of a hemisphere or a portion of a hemisphere.
While the above-mentioned liner is operable as-is as a feature of the invention, a weight is attached to the bottom of the flexible liner, and generally at the center of the liner. This weight assists in the gravity-induced falling and flexing of the liner when the chamber is in its inverted position. While in an embodiment of the invention, the above-mentioned weight comprised a metal disk that was physically attached to the liner, it is within the spirit and scope of this invention to use virtually any means to provide greater weight to the liner, and to thereby assist in the gravity-induced falling and flexing of the liner when the chamber is in its inverted position In an embodiment of the invention, the above-described flexible liner was vacuum formed or injection molded Santoprene-brand thermo plastic elastomer material having a thickness of about 1.5 mm, and the above-described weight weighed from about 400 to about 500 grams (i.e., about one pound).
As a feature of the invention, rotation of the chamber is provided by the energization of a bi-directional motor, the motor being controlled by a controller that includes a microprocessor.
In one mode of operation of the control circuitry, the presence of a cat within the chamber is detected by the operation of a switch that is connected to a front-located spring biased/loaded support leg that supports the device on a floor or the like. This support leg is spring-loaded in a downward direction such that entry of the cat into the chamber causes a switch to be actuated from a first switch state to a second switch state. Later, when the cat exits the chamber, this switch is actuated back to the first state. This cycling of the leg switch operates to actuate a timer, and at the end of a timed interval (for example, seven minutes), the above-mentioned motor is energized to rotate the chamber to screen filter the litter and to cause the screen separated waste material to be gravity dumped, thereafter controlling the motor to reset the chamber to its home position. In this mode of operation, should a second cat enter the chamber during the timing interval, the above process is aborted, and the process resets only after the leg switch has again been cycled by the second cat exiting the chamber.
As a feature of the invention, the above-described spring biased support leg is located generally under a front-disposed opening through which a cat passes as it enters the chamber. In the absence of a cat within the chamber, the device is three point supported on a floor or the like by this spring biased support leg and by two physically spaced and fixed position rear legs. When a cat is present within the chamber, thus causing the front of the device to move vertically downward, two physically-spaced and fixed position front legs move down and into engagement with the floor as the movable leg actuates the above described switch, thus providing a more stable four-point support for the device when a cat is present in the chamber.
In another mode of operation, a manually-operable switch is provided to initiate the above-described litter cleaning cycle, and should this cycling switch be actuated during the above-described timing interval, the timing interval is aborted, and the above-described litter-cleaning cycle begins immediately. As a feature of the invention, this mode of operation can be prevented when it is sensed that a second cat has entered the chamber.
In another mode of operation, a manually-operable switch is provided to control the above-described motor in a manner to cause the chamber to rotate to a position whereat the litter itself to be gravity dumped out of the chamber, thus enabling fresh litter to be introduced into the chamber. In a related mode of operation, a manually-operable switch is provided to control the motor to cause the chamber to rotated to a position whereat new litter can be gravity dumped down into the chamber.
As an additional feature of the invention, three indicator lights (LEDs) are provided to indicate the state of operation of the device. Energization of a green OK/waiting light indicates that the chamber is in its home position, awaiting use by an animal. Energization of a yellow cycling/in-use light indicates that the above-described motor is operating to rotate the chamber. Energization of a red light indicates that an animal is within the chamber. Energization of a red sensor/timing light indicates that the above-mentioned control circuitry is measuring the above-described time interval, prior to the beginning of a litter cleaning cycle. In a failure mode, all three of the above-described lights flash.
In another mode of operation, a manually-operable switch is provided to control the above-described motor to cause the chamber to rotate to a position whereat openings within the chamber are located to provide for the convenient placing of a new supply of litter within the chamber.
These and other features and advantages of the invention will be apparent to those of skill in the art upon reference to the following detailed description, which description makes reference to the drawing.